Rh-Mn-Sb Heusler compounds in thin films

Esther de Prado¹, Artem Shamardin¹, Stanislav Cichoň¹, Jan Duchoň¹, Michal Rameš¹, Ladislav Fekete¹, Jaromír Kopeček¹, Šimon Šťastný², Aleš Melzer², Michal Hubert², Martin Veis², Ján Lančok¹, Oleg Heczko¹

¹FZU-Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, Prague 18000, Czech Republic

²Institute of Physics of Charles University, Ke Karlovu 2026/5, Prague 12116, Czech Republic

Heusler compounds constitute a broad family of intermetallic materials, with more than 1500 possible compositions reported to date. Among them, the Rh–Mn–Sb system has attracted scientific interest for nearly half a century¹. However, although bulk Rh–Mn–Sb alloys were studied several decades ago, experimental work on this system has since remained very limited, and thin films have not been explored. In this context, Rh₂MnSb full-Heusler thin films were epitaxially grown for the first time on MgO(001) substrates by DC magnetron sputtering at deposition temperatures of 600, 700, and 800 °C². Films with a nominal thickness of 200 nm were systematically characterized in terms of their structural, morphological, optical, magneto-optical, and magnetic properties. The sample deposited at 600 °C was close to stoichiometric and exhibited an almost perfectly ordered L2₁ structure. All films exhibited a tetragonal structure and a regular twinned microstructure, in which most twin domains were oriented with the c-axis perpendicular to the film surface, presumably as a result of the constraint imposed by the substrate. Magnetic measurements for the film grown at 600 °C yielded a Curie temperature of about 220–275 K and a saturation magnetization of approximately 55 emu/g at 10 K, both close to bulk values, while magneto-optical Kerr measurements indicated paramagnetic behavior at room temperature. These results demonstrate the potential of Rh₂MnSb thin films and motivate further work aimed at improving compositional precision and structural control.

Figure 1: (a) AFM topography image of a Rh₂MnSb film deposited at 600 °C; (b) structural model of twin-related tetragonal Rh₂MnSb variants and corresponding {220} pole figure; and (c) thermomagnetic curves measured at 0.01 T.

1.         F.A. Hames, J. Crangle, “Ferromagnetism in Heusler-Type Alloys Based on Platinum-Group or Palladium-Group Metals,” Journal of Applied Physics 42 (1971) 1336–1338.

2.         Shamardin, A.; Cichoň, S.; de Prado, E.; Duchoň, J.; Rameš, M.; Fekete, L.; Kopeček, J.; Šťastný, Š.; Melzer, A.; Hubert, M.; Veis, M.; Lančok, J.; Heczko, O. Twinning in ferromagnetic Heusler Rh₂MnSb epitaxial thin films. Journal of Alloys and Compounds 1042 (2025) 184143